“Our hope is this work will help lay the basic science groundwork for an entirely new avenue of research where we develop non-invasive tools to help treat [these] people.”

1m Brits have dementia

Around 850,000 Brits currently have dementia - and the figure is expected to hit one million within a decade.

There is currently no cure, although some drugs can limit the symptoms.

The study, published in the journal Nature Neuroscience, involved 84 participants. Half were in their 20s and half in their 60s and 70s.

Scientists tested their working memory before and after 25-minutes of electrical stimulation, using caps with embedded electrodes.

They tailored the treatment to each individual’s “sweet spot” based on the frequency of their brain waves.

Brain boost

The team found older adults’ working-memory improved to resemble that of younger adults as a result.

Commenting on the study, Dr Vladimir Litvak, from the Wellcome Centre for Human Neuroimaging at University College London, said: “This is an interesting and exciting study showing that non-invasive brain stimulation can improve the performance in a task testing working memory in healthy older adults and bring it to a range comparable with younger people.”

But there was no evidence the technique boosted older people’s recall – which is affected by Alzheimer’s.